Authentication of Turkish propolis through HPTLC fingerprints combined with multivariate analysis and palynological data and their comparative antioxidant activity

Abstract

Propolis is a honeycomb product having very diverse chemical composition and possessing a broad spectrum of biological activities. This study comprehensively evaluated the phenolic profile of Turkish propolis by using a high performance thin-layer chromatographic (HPTLC) method in combination with image analysis and pattern recognition technique. Also, botanical origin of each propolis sample was determined by comparison of HPTLC fingerprints of propolis samples with that of plant bud extracts and also by palynological analysis. Moreover, HPTLC coupled with 2,2-diphenyl-1-picrylhydrazyl (DPPH˙) detection technique was used for screening of antioxidant activity of each separated compounds directly on the plate. Results of the present study have demonstrated that Turkish propolis could be classified under three main types; i.e. orange (O) (originated from Populus nigra L.), blue (B) (originated from Populus tremula L.) and nonphenolic types. Palynological analysis have shown that dominant pollen grains (>%45) in propolis samples were: Fabaceae, Lamiaceae, Rosaceae, Castanea sativa Mill., Lotus corniculatus L., Salix spp. In addition, HPTLC-DPPH˙ results showed that O-type of propolis exerted higher antioxidant activity than the other propolis types. Moreover, quercetin, caffeic acid, caffeic acid phenyl ester, pinobanksin and galangin had significant contribution to the antioxidant activity of propolis.